package com.mmall.util;

import com.mmall.pojo.User;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.type.TypeReference;

import java.io.IOException;
import java.text.SimpleDateFormat;

/**
 * 高可复用，可用于生产环境
 * @author sunqy
 * @create 2019/9/14
 */
@Slf4j
public class JsonUtil {
    private static ObjectMapper objectMapper = new ObjectMapper();
    static {
        //对象的所有字段全部列入
        objectMapper.setSerializationInclusion(Inclusion.ALWAYS);
        //取消默认转换timestamps
        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,false);
        //取消默认转换timestamp形式
        objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS,false);
        //所有的日期格式都统一为以下的样式
        objectMapper.setDateFormat(new SimpleDateFormat(DateTimeUtil.STANDARD_FORMAT));
        //忽略在json字符串中存在，但是在java对象中不存在对应属性的情况，防止错误
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);
    }

    public static <T> String obj2str(T obj){
        if (obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String)obj : objectMapper.writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("parse object to string error", e);
            return null;
        }
    }

    public static <T> String obj2strPretty(T obj){
        if (obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String)obj : objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("parse object to string error", e);
            return null;
        }
    }

    public static <T> T string2obj(String str, Class<T> clazz){
        if (StringUtils.isEmpty(str) || clazz == null){
            return null;
        }
        try {
            return clazz.equals(String.class)? (T)str:objectMapper.readValue(str,clazz);
        } catch(Exception e) {
            log.error("parse string to object error", e);
            return null;
        }
    }

    public static <T> T string2obj(String str, TypeReference<T> typeReference){
        if (StringUtils.isEmpty(str) || typeReference == null){
            return null;
        }
        try {
            return (T)(typeReference.getType().equals(String.class)? (T)str:objectMapper.readValue(str,typeReference));
        } catch(Exception e) {
            log.error("parse string to object error", e);
            return null;
        }
    }

    public static <T> T string2obj(String str, Class<?> collectionClass,Class<?>... elementClasses) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass,elementClasses);
        try {
            return objectMapper.readValue(str,javaType);
        } catch(Exception e) {
            log.error("parse string to object error", e);
            return null;
        }
    }
}
